Project Summary A state of the art metabolomics core is a vital part of the Undiagnosed Diseases Network (UDN). The Undiagnosed Diseases Network Metabolomics Core (UDNMC) is a partnership that combines the state of the art analytical and bioinformatics capabilities of the Pacific Northwest National Laboratory (PNNL), with clinical and genetic expertise from Oregon Health & Science University (OHSU). The integration of this combined expertise will facilitate the linkage of novel metabolites or patterns of metabolites identified by the metabolomics core to the underlying metabolic and genetic derangements, as well as clinical signs and symptoms, and to translate this knowledge into specific clues regarding the genetic etiology of the patient?s disorder. The major goal of the UDNMC is to provide metabolomics assays and computational resources that will address the enormous challenges in developing a modern approach to the use of metabolomics in the diagnosis of disease. For this supplement, the metabolomics core will perform metabolomics and lipidomics analyses of plasma, urine, and cerebrospinal fluid from individuals with undiagnosed disease, and perform advanced clustering analyses of the data in order to identify panels of metabolites and/or lipids that may explain patient disease. This work is significant because it applies state-of-the-art and advanced metabolomics and lipidomics measurements and bioinformatics analyses to diagnose rare disease. This work is innovative because it combines the collective expertise in mass spectrometry and omics measurements of the PNNL team with the expertise in inherited metabolic disease and deep semantic phenotyping of the OHSU team and applies it to the challenge of diagnosis of disease.